1. Field of the Invention
The present invention relates to an information retrieval system, apparatus, and method for selecting suitable database(s) among a plurality of databases for retrieving information. The present invention also relates to a storage medium storing the processing programs for executing the above method.
This application is based on Japanese Patent Application No. Hei 10-002452, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Recently, along with the progress of network technologies, the number of databases for retrieving information via a personal computer, work station, or the like has been increased. When a user of a personal computer or work station is going to retrieve a specific information item from a database which is connected to a network, if all databases are searched, the cost necessary for retrieval is high and a great number of data items are examined. Therefore, in such a case, it is required to select suitable database(s) from among a plurality of databases.
As a technique of selecting suitable database(s) from among a plurality of databases on a network, the following are known: a database selection processor disclosed in Japanese patent application, First Publication, No. Hei 5-101101 (called the first conventional example, hereinbelow), an information retrieval system disclosed in Japanese patent application, First Publication, No. Hei 7-56932 (called the second conventional example, hereinbelow), a database selector disclosed in Japanese patent application, First Publication, No. Hei 7-85072 (called the third conventional example, hereinbelow), and a database selection system disclosed in Japanese patent application, First Publication, No. Hei 9-153058 (called the fourth conventional example, hereinbelow).
In the first conventional example, relevant fields are narrowed down to a few candidates in accordance with a user""s selecting and designating operation based on data about the field for search and about the relevant databases, and a database is selected. In the second conventional example, a database is selected with reference to a retrieval term input by a user. In the third conventional example, a score for each database with respect to a retrieval term input by a user is calculated with reference to a database determination table, and a database is selected in accordance with calculated scores. In the fourth conventional example, an expectation is calculated based on the number of records in each database corresponding to a retrieval term, and a database is selected in accordance with calculated expectations.
However, in the above first conventional example, it is necessary for a user to prepare all data about the field for search and about the relevant databases; thus, operations are troublesome. In the above second conventional example, if a search is executed using a plurality of retrieval terms, database selection is not performed using all the retrieval terms. Therefore, in this case, the accuracy in selecting suitable databases is degraded.
In addition, in the above third conventional example, the database determination table is generated based on documents which are randomly extracted from databases; thus, it is necessary to access databases only for generating the database determination table. Therefore, processing time and cost are increased. In the above fourth conventional example, it is necessary to manage all retrieval terms and the number of records corresponding to each retrieval term stored in each database. Therefore, if a database is updated, each number of records must also be revised, and a large amount of memory area is necessary. Accordingly, processing time and cost are increased.
In order to solve the above problems, it is an objective of the present invention to provide an information retrieval system, apparatus, and method for automatically selecting suitable database(s) from among a plurality of databases via a simple operation, with excellent accuracy. It is another objective of the present invention to provide a storage medium storing processing programs for executing the above method.
To achieve the above objectives, the present invention provides an information retrieval system including a plurality of databases storing information items and an information retrieval apparatus, connected via a network to the plurality of databases, for selecting a database from among the plurality of databases, issuing a data-search request via the network to the selected database, and receiving search results in response to the request via the network:
wherein the information retrieval apparatus comprises:
evaluated value storing means for storing a plurality of terms and related evaluated values, each term corresponding to a plurality of evaluated values assigned to the plurality of databases;
evaluated value extracting means for extracting the evaluated values which have been respectively assigned to the plurality of databases and correspond to each of designated retrieval terms;
database selecting means for:
calculating evaluated values which are respectively assigned to the plurality of databases, based on the evaluated values extracted for each retrieval term by the evaluated value extracting means, and
selecting one or more databases to be searched from among the plurality of databases in accordance with the calculated evaluated values for each database;
search requesting means for issuing a data-search request based on the retrieval terms to the databases selected by the database selecting means; and
evaluated value correcting means for correcting the evaluated values which are stored in the evaluated value storing means and correspond to the retrieval terms, in accordance with search results in response to the data-search request.
According to the above information retrieval system, when data are retrieved from a plurality of databases based on a plurality of retrieval terms, evaluated values assigned to the plurality of databases are extracted by the evaluated value extracting means for each retrieval term, and evaluated values for each database are newly calculated based on the extracted evaluated values. Therefore, in the above information retrieval system, databases to be searched can be selected with a plurality of retrieval terms and thus the accuracy for selecting suitable databases is superior.
Every time the databases are accessed, the evaluated values stored in the evaluated value storing means are updated by the evaluated value correcting means, in accordance with the actual search results. Therefore, if data are updated on the database side, the evaluated values can be updated in consideration of the updated data. Therefore, the above information retrieval system can achieve further superior accuracy for selecting databases to be searched. In addition, no operation by the user is necessary for updating the evaluated values; thus, no complicated operation needs to be carried out by the user.
The present invention also provides an information retrieval apparatus for selecting a database from among a plurality of databases and issuing a data-search request to the selected database, comprising:
evaluated value storing means for storing a plurality of terms and related evaluated values, each term corresponding to a plurality of evaluated values assigned to the plurality of databases;
evaluated value extracting means for extracting the evaluated values which have been respectively assigned to the plurality of databases and correspond to each of designated retrieval terms;
database selecting means for:
calculating evaluated values which are respectively assigned to the plurality of databases, based on the evaluated values extracted for each retrieval term by the evaluated value extracting means, and
selecting one or more databases to be searched from among the plurality of databases in accordance with the calculated evaluated values for each database;
search requesting means for issuing a data-search request based on the retrieval terms to the databases selected by the database selecting means; and
evaluated value correcting means for correcting the evaluated values which are stored in the evaluated value storing means and correspond to the retrieval terms, in accordance with search results in response to the data-search request.
According to the above information retrieval apparatus, when data are retrieved from a plurality of databases based on a plurality of retrieval terms, evaluated values assigned to the plurality of databases are extracted by the evaluated value extracting means for each retrieval term, and evaluated values for each database are newly calculated based on the extracted evaluated values. Therefore, in the above information retrieval apparatus, databases to be searched can be selected with a plurality of retrieval terms and thus the accuracy for selecting suitable databases is superior.
Every time the databases are accessed, the evaluated values stored in the evaluated value storing means are updated by the evaluated value correcting means, in accordance with the actual search results. Therefore, if data are updated on the database side, the evaluated values can be updated in consideration of the updated data. Therefore, the above information retrieval apparatus can achieve further superior accuracy for selecting databases to be searched. In addition, no operation by the user is necessary for updating the evaluated values; thus, no complicated operation needs to be carried out by the user.
The information retrieval apparatus may further comprise an input means for inputting the retrieval terms. In this case, the evaluated value extracting means may extract the evaluated values which correspond to each of the retrieval terms input from the input means.
The information retrieval apparatus may further comprise an input means for inputting a character sequence; and retrieval term extracting means for analyzing the character sequence input from the input means and extracting retrieval terms. In this case, the evaluated value extracting means may extract the evaluated values which correspond to each of the retrieval terms extracted by the retrieval term extracting means.
In the information retrieval apparatus, the retrieval terms may be respectively weighted. In this case, the database selecting means may calculate the evaluated values which are respectively assigned to the plurality of databases, further based on the weights assigned to each retrieval term.
In the information retrieval apparatus, the evaluated value storing means may comprise a first storage means for storing a plurality of terms and related fields, each term corresponding to a field; and a second storage means for storing, in a correspondence relationship, the fields stored in the first storing means and evaluated values assigned to the plurality of databases for each field. In this case, the evaluated value extracting means may comprise a first extracting means for extracting the fields corresponding to the retrieval terms from the first storage means, and a second extracting means for extracting the evaluated values which respectively correspond to the fields extracted by the first extracting means and correspond to the plurality of databases. According to this arrangement, the capacity of a storage medium necessary for the evaluated value storing means can be reduced.
In the information retrieval apparatus, the database selecting means may select a plurality of databases in accordance with the calculated evaluated values for each database. In this case, the search requesting means may issue a data-search request to the plurality of databases selected by the database selecting means; and the evaluated value correcting means may correct the evaluated values in a manner such that a database from which a larger number of data were retrieved is detected with reference to the search results, and the evaluated values assigned to this database with respect to the retrieval terms (or with respect to the fields which correspond to the retrieval terms) are corrected to higher values. According to this arrangement, if a database is updated and the amount of data thereof is increased, the evaluated values assigned to the database are upgraded. In addition, such a data correction in the information retrieval apparatus can correspond to each data update on the database side. Therefore, according to the present arrangement, databases including more data relating to the retrieval terms can be selected.
The information retrieval apparatus may further comprise a retrieval term determining means for determining, for each retrieval term, whether a term corresponding to the retrieval term is stored in the evaluated value storing means; and a register means for newly registering the retrieval term which was determined by the retrieval term determining means as having no corresponding term stored in the evaluated value storing means, and related evaluated values to the evaluated value storing means. According to this arrangement, if a data search is performed using a retrieval term which has not yet been stored in the evaluated value storing means, evaluated values corresponding to this retrieval term can be automatically registered, and no complicated operation by the user is necessary.
The present invention also provides an information retrieval method for selecting a database from among a plurality of databases and issuing a data-search request to the selected database, comprising:
an evaluated value extracting step of extracting evaluated values which correspond to each of designated retrieval terms and are assigned to the plurality of databases from an evaluated value storing means which stores the evaluated values assigned to the plurality of databases and the retrieval terms in a correspondence relationship;
a database selecting step of:
calculating evaluated values which are respectively assigned to the plurality of databases, based on the evaluated values extracted for each retrieval term in the evaluated value extracting step, and
selecting one or more databases to be searched from among the plurality of databases in accordance with the calculated evaluated values for each database;
a search requesting step of issuing a data-search request based on the retrieval terms to the databases selected in the database selecting step; and
an evaluated value correcting step of correcting the evaluated values which are stored in the evaluated value storing means and correspond to the retrieval terms, in accordance with search results in response to the data-search request.
The present invention also provides a computer readable storage medium storing a program for selecting a database from among a plurality of databases and issuing a data-search request to the selected database, the program comprising:
an evaluated value extracting step of extracting evaluated values which correspond to each of designated retrieval terms and are assigned to the plurality of databases from an evaluated value storing means which stores the evaluated values assigned to the plurality of databases and the retrieval terms in a correspondence relationship;
a database selecting step of:
calculating evaluated values which are respectively assigned to the plurality of databases, based on the evaluated values extracted for each retrieval term in the evaluated value extracting step, and
selecting one or more databases to be searched from among the plurality of databases in accordance with the calculated evaluated values for each database;
a search requesting step of issuing a data-search request based on the retrieval terms to the databases selected in the database selecting step; and
an evaluated value correcting step of correcting the evaluated values which are stored in the evaluated value storing means and correspond to the retrieval terms, in accordance with search results in response to the data-search request.